Patient Global Impression Questions for Activity-Induced Symptoms in Participants With PAH

This is an observational, multicenter, single-day, Phase 2 study. This study will include a 14-day Screening Period and Study Day 1 clinic visit. Participants will be required to perform an activity to induce symptoms of PAH, and participants' severity of self-reported symptoms of PAH will be measured from pre-activity, immediately after the activity, and through the 30-minute recovery. Participants will be asked about their PAH symptoms using 3 Patient Global Impression of Severity (PGI-S) questions that address their overall PAH symptoms, shortness of breath, and physical fatigue. PAH symptoms will be induced via the Incremental Shuttle Walk Test (ISWT). The ISWT used in this study required the participant to walk back and forth on a 10-meter course. The total number of shuttles completed by a participant during the Screening ISWT will be the maximum targeted for that participant during the remaining ISWTs in the study. After Screening, participants will be assigned to 1 of 2 cohorts based on PAH medications as prescribed by their physician: Cohort A will include participants who are currently prescribed and using inhaled treprostinil for the treatment of PAH and Cohort B will include participants who are taking other PAH medications (instead of inhaled treprostinil). The study also includes 2 periods. One period for participants in Cohort A (Treprostinil Users), included an ISWT initiated within 30 minutes of the previous dose (expected peak level) and the other period included an ISWT within 3 to 4 hours of the previous dose of inhaled treprostinil (expected trough level). Participants in Cohort B (Non-Treprostinil Users), an ISWT will be initiated approximately 4 hours after the morning dose of PAH medication (Period 1) and an ISWT initiated at least 1 hour following completion of the previous ISWT (Period 2). Participants will be provided at least a 1-hour period for rest between ISWTs (until participant feels they are rested enough to perform again at their baseline level) prior to Period 2 assessments.